An electrolytic process (electrolytic treatment) is a technique used for various treatments such as a plating treatment and an etching treatment.
In order to uniformly perform the plating treatment, for example, the plating treatment disclosed in Japanese Laid-Open Patent Publication No. 2015-004124 has been suggested. In the plating treatment, a direct electrode and a counter electrode (a workpiece) are disposed such that a plating liquid is interposed therebetween, and an indirect electrode is disposed to form an electric field in the plating liquid. Then, metal ions in the plating liquid are moved to the counter electrode side by the electric field formed using the indirect electrode, and a voltage is applied between the direct electrode and the counter electrode so as to reduce the metal ions moved to the counter electrode side.
In this case, since the movement of the metal ions by the indirect electrode and the reduction of the metal ions by the direct electrode and the counter electrode are individually performed, the reduction of the metal ions may be performed in a state where the metal ions are uniformly integrated on the counter electrode side, and as a result, the uniformization of the plating treatment is implemented.